Feasibility Study on a Microwave Heating Applicator Using Electromagnetic Coupling

A new type of microwave heating applicator using electromagnetic coupling is proposed. A great feature of the applicator is easiness of setting the heated sample as well as the applicator itself. Two half-wavelength resonators on a dielectric substrate provide the electromagnetic coupling, and the heated sample is placed between the resonators. The applicator is designed via 3D electromagnetic simulator. A behavior like electromagnetic coupling is confirmed from the simulation results. Microwaves can be absorbed in the sample (ultrapure water) better when the output port is open than it is matched to 50 Ω. Microwave leakage is lower than the ICNIRP guideline of the basic restriction for the occupational exposure at a distance of 10 cm from the applicator. Demonstration experiments verified that 4.3 ml of the sample can be heated above 80°C within 5 minutes at a 2.45 GHz microwave power of 10 W.